(Invited) Finely Controlled Heterointerfaces between Ge(111) and Metallic Alloys or Insulators for Next Generation Ge-Based Devices

Abstract

For next generation Ge-based devices, we have developed epitaxial growth techniques of high-performance ferromagnetic alloys or high-k insulators on Ge(111). By using low-temperature MBE or PLD, high-quality heterointerfaces for source/drain or gate-stack structures can be achieved, respectively. We detect spin transport in n-Ge(111) and p-Ge(111) through the high-quality ferromagnetic alloys/Ge(111). In addition, the Fermi level pinning is markedly suppressed even for the metal/Ge contacts and the Schottky barrier height of the metal/p-Ge contacts can be controlled by the metal work function. Finally, we show a new approach for gate-stack structures with crystalline high-k La2O3 layers. We obtained atomically smooth heterointerfaces between La2O3 and Ge(111). These results will open a road to integrate finely controlled structures into next generation Ge devices.